Low dose 13C-Urea breath test (13C-UBT) with citrate is equally reliable for the detection of Helicobacter pylori infection in Chinese

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Non-H. pylori, non-NSAID duodenal ulcers: clinical and endoscopic characteristics

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qtl.outbred: Interfacing outbred line cross data with the R/qtl mapping software

<p>Abstract</p> <p>Background</p> <p><b>qtl.outbred </b>is an extendible interface in the statistical environment, R, for combining quantitative trait loci (QTL) mapping tools. It is built as an umbrella package that enables outbred genotype probabilities to be calculated and/or imported into the software package R/<b>qtl</b>.</p> <p>Findings</p> <p>Using <b>qtl.outbred</b>, the genotype probabilities from outbred line cross data can be calculated by interfacing with a new and efficient algorithm developed for analyzing arbitrarily large datasets (included in the package) or imported from other sources such as the web-based tool, GridQTL.</p> <p>Conclusion</p> <p><b>qtl.outbred </b>will improve the speed for calculating probabilities and the ability to analyse large future datasets. This package enables the user to analyse outbred line cross data accurately, but with similar effort than inbred line cross data.</p

Normal 24-hour ambulatory proximal and distal gastroesophageal reflux parameters in Chinese.

OBJECTIVE: To quantify normal proximal and distal oesophageal acid parameters in healthy Chinese. DESIGN: Observational study. SETTING: University teaching hospital, Hong Kong. SUBJECTS AND METHODS: Twenty healthy adults who were not on medication and were free from gastrointestinal symptoms were recruited by advertisement. Ambulatory oesophageal acid (pH5 minutes, 4/0; and the longest single acid exposure episode, 11.2/3.0 minutes. CONCLUSION: Physiological gastroesophageal reflux occurs in healthy Chinese. These initial data provide a preliminary reference range that could be utilised by laboratories studying Chinese subjects.published_or_final_versio

Crack-Like Processes Governing the Onset of Frictional Slip

We perform real-time measurements of the net contact area between two blocks of like material at the onset of frictional slip. We show that the process of interface detachment, which immediately precedes the inception of frictional sliding, is governed by three different types of detachment fronts. These crack-like detachment fronts differ by both their propagation velocities and by the amount of net contact surface reduction caused by their passage. The most rapid fronts propagate at intersonic velocities but generate a negligible reduction in contact area across the interface. Sub-Rayleigh fronts are crack-like modes which propagate at velocities up to the Rayleigh wave speed, VR, and give rise to an approximate 10% reduction in net contact area. The most efficient contact area reduction (~20%) is precipitated by the passage of slow detachment fronts. These fronts propagate at anomalously slow velocities, which are over an order of magnitude lower than VR yet orders of magnitude higher than other characteristic velocity scales such as either slip or loading velocities. Slow fronts are generated, in conjunction with intersonic fronts, by the sudden arrest of sub-Rayleigh fronts. No overall sliding of the interface occurs until either of the slower two fronts traverses the entire interface, and motion at the leading edge of the interface is initiated. Slip at the trailing edge of the interface accompanies the motion of both the slow and sub-Rayleigh fronts. We might expect these modes to be important in both fault nucleation and earthquake dynamics.Comment: 19 page, 5 figures, to appear in International Journal of Fractur

Hedgehog Spin-texture and Berry's Phase tuning in a Magnetic Topological Insulator

Understanding and control of spin degrees of freedom on the surfaces of topological materials are key to future applications as well as for realizing novel physics such as the axion electrodynamics associated with time-reversal (TR) symmetry breaking on the surface. We experimentally demonstrate magnetically induced spin reorientation phenomena simultaneous with a Dirac-metal to gapped-insulator transition on the surfaces of manganese-doped Bi2Se3 thin films. The resulting electronic groundstate exhibits unique hedgehog-like spin textures at low energies, which directly demonstrate the mechanics of TR symmetry breaking on the surface. We further show that an insulating gap induced by quantum tunnelling between surfaces exhibits spin texture modulation at low energies but respects TR invariance. These spin phenomena and the control of their Fermi surface geometrical phase first demonstrated in our experiments pave the way for the future realization of many predicted exotic magnetic phenomena of topological origin.Comment: 38 pages, 18 Figures, Includes new text, additional datasets and interpretation beyond arXiv:1206.2090, for the final published version see Nature Physics (2012

Label-free cell cycle analysis for high-throughput imaging flow cytometry

Imaging flow cytometry combines the high-throughput capabilities of conventional flow cytometry with single-cell imaging. Here we demonstrate label-free prediction of DNA content and quantification of the mitotic cell cycle phases by applying supervised machine learning to morphological features extracted from brightfield and the typically ignored darkfield images of cells from an imaging flow cytometer. This method facilitates non-destructive monitoring of cells avoiding potentially confounding effects of fluorescent stains while maximizing available fluorescence channels. The method is effective in cell cycle analysis for mammalian cells, both fixed and live, and accurately assesses the impact of a cell cycle mitotic phase blocking agent. As the same method is effective in predicting the DNA content of fission yeast, it is likely to have a broad application to other cell types

Evaluation of three near patient tests for the diagnosis of Helicobacter pylori (H. pylori) infection in Chinese population

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